Gas not going to injectors(replaced filter and fuel pump)

starting
gasoline
saab

#1

So have a 1991 Saab 900 about a 3 month’s ago I bought it and each time I would fill up the tank the gas light would always be on well after awhile of driving it for about a month it broke down. I would just be driving and all of a sudden it would shut off, and won’t start for a few hours and now it won’t start at all just crank I’ve replaced the fuel pump and it’s pumping though the line but I took the injectors out to see if it would spray when cranking and it’s not. What could it be someone please help!


#2

I’m assuming the “gas light” is that warning light on the dash that says the gas tank is nearly empty. That’s probably a problem w/the fuel gauge sender unit inside the gas tank, and I doubt that is related to the no-start problem. You’re sure there’s enough gas in the gas tank, right? Here’s some guesses for the no-start problem

  • Computer must sense engine is rotating before it will spray injectors, so engine rotation sensor(s) may be bad.

  • Not enough fuel pressure

  • Bad fuse(s)

  • Bad relay(s)

  • Bad engine computer

  • Battery is bad or battery power not getting to the engine computer properly


#3

The tank is full


#4

Probably the next step is to measure the fuel pressure when the pump is running. If you aren’t experienced with this kind of measurement, best to leave it to the pros. Working w/gasoline is very dangerous. I try to avoid anything involving the possibility of spilled gas myself.


#5

Make sure the injectors are pulsing while the engine is cranked over. Noid light, VOM, stethoscope to listen to them while someone cranks the engine are several ways of easily checking them.

With the key in the RUN position a voltmeter can be used to verify that power is present at the injector connectors. If power is present and the injector grounds are not being made and broken inside the PCM then further diagnosis will be needed.

Wild guessing a crank sensor if no pulse or even a bad ignition switch. Those switches being located down low between the seats can be prone to dirt, cookie crumbs, spilled soda or coffee, etc and fail due to that.

I’d check for injector power and pulse and go from there.


#6

You sir might have a vapor lock. I do not think your sensors are bad nor your ignition. In older cars you have to check the venting system in the gas tank. A vapor lock is when gas is evaporated to air. And the pumps are designed to pump liquid and not air and causes problems and the gas cant get to the injectors and the engine does not turn on, because it is pumping air instead of a liquid. Go and have your car checked for a clogged venting system. It might fix the problem. I would check the venting system 2 times a year. This only happens in old cars.